Preheat oven to 200°C (180°C fan bake). Line two large baking sheets with greaseproof paper.
Unroll your puff pastry, cut it lengthways into 3 strips and spoon the puree over the pastry strips, spreading evenly across.
Put the icing sugar in a small sieve or tea strainer with the cinnamon and sprinkle over the blueberry puree.
Roll each strip across the length to make 3 long sausages. Cut each sausage into 1 cm pieces and lay them out onto the baking sheets spaced 3 cm apart.
Bake for 20-25 minutes until golden brown. Cool on a wire rack and serve sprinkled with icing sugar